Aux fan question

Been gone for some time,nice to have a XJ again,makes #4. I sold the TJ and picked up a clean 87 XJ with 110K and a D44 rear diff, Im weeding out a few things,
first is the auxilary fan supposed to come on reguardless of engine temp when the AC is turned on?
#2 I recall reading somewhere a D44 equipted XJ is more prone to vibes in back when lifted due to diff design? true or false and is a SYE the only cure?
Thanks a bunch guys/gals.

I believe the pinion is longer (I'm not sure - can anyone confirm) for the D44 than for the D35 or the C8.25 - which means that lifting your rig will cause changes in u-joint operating angle that much more quickly.

That's not a "flaw" of the axle - just simple geometry. You're probably going to need a transfer case drop and/or tapered shims that much more quickly, but that should see to the problem.

and yes, i belive the aux fan is supposed to come on with AC, regardless of temp....

Yes, that is correct.

JNickel101 said:

and yes, i belive the aux fan is supposed to come on with AC, regardless of temp....

Click to expand...

dyna said:

I recall reading somewhere a D44 equipted XJ is more prone to vibes in back when lifted due to diff design? true or false and is a SYE the only cure?
Thanks a bunch guys/gals.

Click to expand...

5-90 said:

I believe the pinion is longer (I'm not sure - can anyone confirm) for the D44 than for the D35 or the C8.25 - which means that lifting your rig will cause changes in u-joint operating angle that much more quickly.

That's not a "flaw" of the axle - just simple geometry. You're probably going to need a transfer case drop and/or tapered shims that much more quickly, but that should see to the problem.

Click to expand...

Yeah the pinion is about 3/4 of an inch longer so it takes a slightly shorter shaft. In theory, yes it would be a little more prone to vibration when lifted - in reality, considering the length of the driveshaft, it's not anything to be concerned with.

I'm not so sure about the fan and A/C question. I had heard the same thing, but my 01 doesn't always run aux fan just because A/C is cycling. It might depend if the engine is still in the warmup cycle. I haven't had any overheating issues, so I lost interest pretty quickly when I noticed it.